Recent regulatory actions have made it important to alter practices in the trucking and related industries. Specifically, it had been the practice for years for truck drivers to allow their engines to idle for many hours, often all night, so as to provide either heat or air conditioning to the cab, for comfortable sleeping. This has now been disallowed, necessitating some other means of providing temperature control for the cab. Some truck stops provide plug-in “shore power” for powering electrically-operated heating and air conditioning equipment, but this is not always convenient, and is expensive where possible. It would therefore be desirable to provide some way to control the cab temperature during extended layover periods that did not necessitate running the truck's engine, or connection to a “shore power” outlet.
Another new practice is necessitated by regulations mandating that truck and trailer roofs be cleared of snow and ice before driving. While it is obviously desirable to do so for reasons of safety, manual snow and ice removal can be quite burdensome and dangerous for the drivers. It would therefore be desirable to provide a way to keep the truck and trailer roofs free of snow and ice buildup, especially while stopped for the night, and which again does not involve running the truck engine or connection to an external power supply of some kind.
It would also be desirable to provide power to the truck cab to supply electrical “comfort loads”, such as communication and entertainment systems for the driver, in a manner which would not require the truck engine to run, not require power to be drawn from the truck's battery, nor to require a “shore power” connection.
The following summarizes the pertinent art known to the inventors:
Chinese patent CN201604567 shows a solar-powered refrigerated trailer, with energy storage capacity provided by batteries.
Italian patent IT1151980 shows powering loads such as lights, air conditioning and the like from a separate battery charged by solar cells mounted on the tractor or trailer.
U.S. Pat. No. 4,780,618 to Wareman et al shows powering certain tractor components from an engine of a refrigeration unit comprised by a trailer while the tractor engine is shut off.
U.S. Pat. No. 5,333,678 to Mellum et al shows an auxiliary power unit for a tractor that supplies HVAC capability and keeps the main engine warm when shut off.
U.S. Pat. No. 6,812,582 to Kennedy shows driving the air conditioning compressor of a tractor with an electric motor, itself powered by a diesel generator.
U.S. Pat. No. 7,151,326 to Jordan shows providing an auxiliary power unit on a trailer for supplying power to a tractor when the tractor engine is shut off. Solar panels are mentioned as one possible power source (see col. 6, line 3) although the primary power source appears to be the engine of a refrigeration unit on the trailer.
US patent application 2004/0231831 of Houck shows another auxiliary power supply to be added to a tractor.
US patent application 2007/0221370 of Allen shows an auxiliary power system for a tractor's HVAC unit comprising a second battery bank.
US patent application 2008/174174 of Burns et al shows a regeneration system for a trailer whereby energy can be captured on down-grades and under braking and used to power the trailer wheels for propulsion, or for other purposes.
US patent application 2009/0260377 of Miller et al shows a modularized HVAC system for a tractor.
US patent application 2010/0146821 of Kaesler et al shows a resistive heating element to be mounted on the inside of the roof of a trailer to prevent ice and snow buildup.
US patent application 2010/0212659 of Carpoff shows trailer-mounted solar panels to be used to provide power to construction sites and other locations to which the power grid does not extend.
US patent application 2010/0263703 of Reichart et al shows solar panels to be mounted to the roof of a trailer to power the air handling system thereof; batteries are provided to store energy during darkness.
Patent Cooperation Treaty application WO2009/89160 of Jordan is nearly incomprehensible, but appears to disclose an auxiliary power system for a tractor that provides several different output voltages.
Finally, Patent Cooperation Treaty application WO2010/94875 of Porcellato shows a system for controlling the charging of a battery.
It will be appreciated that many of the above references showing use of an auxiliary engine, e.g., that of a trailer refrigeration unit, to power truck loads during periods when the truck is stopped would also involve running an engine for long periods of time, which is also very undesirable. What is needed is a system for powering such loads, and others, that does not require running an engine to meet those load requirements. Such an auxiliary power system would be useful in keeping a truck cab comfortable for long stationary periods without running the engine. Such a system would be useful likewise for buses, emergency vehicles and the like, wherein the driver may be required to remain in the cab for lengthy periods, without idling the engine.